Fuse plug



Feb. 3, 1942 J. BALDWIN ET AL 2,271,729

FUSE PLUG Filed May 6; 1941 INVENTOR-S: Jo/m Baldwin BY Wi/Zl'amfil'lienrana MJ/T- M...

AT URNEY Patented Feb. 3, 1942 UNITED FUSE PLUG John Baldwin, Brooklyn,and William Hillenbrand, Rigo Park, Long Island, N. Y.

Application May 6, 1941, Serial No. 392,060

2 Claims.

This invention relates to fuse plugs and more particularly to a fuseplug having a mechanical indicating means to indicate that the fuse hasblown out.

In accordance with the invention I provide a fuse plug having anindicating member that does not form a part of the electric circuit. Theindicating member consists of a rod that is slidable in an aperture inthe fuse cover. The rod is normally retracted by a light spring into thehollow interior of the fuse. The fuse wire is connected with a springwhich is normally tensioned. When the fuse wire breaks, the spring isreleased and forces the indicatin rod outwards to indicate that the fusehas blown out. Since the indicating member does not form part of theelectric circuit it is never alive and hence cannot cause an electricshock.

It is among the objects of the invention to provide an improved fuseplug having an indicating member for indicating that the fuse has blownout, said indicating member being insulated from the electric currentflowing through the fuse.

These and further objects of the invention will become more apparent inthe following description of a preferred embodiment of the inventionillustrated in the drawing, wherein:

Fig. 1 is a longitudinal sectional view of a fuse plug of the invention,

Fig. 2 is a longitudinal sectional View similar to Fig. 1 showing thefuse plug in its blown out position.

Fig. 3 is a top plan View of the fuse plug of Fig. 1.

Referring to the drawing, the fuse plug in accordance with the inventioncomprises an insulating body III having a cover plate II provided with acentral aperture I2. Insulating body III consists of two portions A andB separated along lines 8 and 9. Line 8 divides cover plate II into twoparts. Portion A also includes the bottom of insulating body I beingseparated from portion B by line 9. This construction facilitates theassembly of the fuse plug of the invention. Insulating body I0 isthreaded and engages with threaded sleeve I3. Sleeve I3 consists of anelectrically conducting material and serves to hold together insulatingportions A and B. Threaded sleeve I3 forms one of the two terminals ofthe plug. The other terminal is formed by center contact I4. Insulatingbody I0 is formed with an interior chamber I5. Center contact I4 andthreaded sleeve I3 are electrically connected by spring I6 and fuse wireII arranged Ill in chamber I5. Spring I6 may be soldered to threadedsleeve I3 as indicated at I8. Insulating body I0 has a passage 20arranged below cover I I through which spring I6 passes. Fuse wire I! isconnected with central contact I4 by metal tape 2|. Rod 22 integral withdisc 23 is slidable in aperture I2. Rod 22 and disc 23 are made ofelectrically insulating material. Spring 24 is provided between disc 23and cover II and normally presses rod 22 into chamber I5.

The operation of my improved fuse plug will now be apparent. In theposition of Fig. 1 rod 22 is nearly flush with the surface of cover IIdue to the action of spring 24, When fuse wire I'I breaks, spring I6 isreleased and presses against disc 23 to force rod 22 out of cover II.Spring 24 is comparatively light so that a small force is sufficient tobring rod 22 in the position of Fig. 2. Passage 20 may be closed bysolder I8.

Various changes and modifications may be made to the details ofconstruction of the in vention without departing from the broader spiritand scope thereof, as set forth in the following claims.

I claim:

1. A fuse plug comprising an insulating housing including a cover andconsisting of two sections, one housing section comprising substantiallyone half of said cover and a semi-cylindrical portion, the other housingsection comprising a base, the other half of said cover and a secondsemi-cylindrical portion, said two semicylindrical portions having anouter thread, a center contact on said base, a metallic threaded sleevearranged for cooperation with the thread on said semi-cylindricalportions and forming a second contact, an insulating indicating memberslidable in an aperture in said cover, a first spring urging saidindicating member into said housing and away from said cover, a fuseconnected with said center contact, a second spring connected with saidfuse, extending through a transversal opening in one of saidsemi-cylindrical portions and connected with said sleeve, said secondspring being normally tensioned by said fuse and being arranged to forcesaid indicating member out of said cover when said fuse blows.

2. A fuse plug comprising an insulating housing including a cover andconsisting of two sections, one housing section comprising substantiallyone half of said cover and semi-cylindrical portion, the other housingsection comprising a base, the other half of said cover and a secondsemi-cylindrical portion, said two semicylindrical portions having anouter thread, a

center contact on said base, a metallic threaded sleeve arranged forcooperation with the thread on said semi-cylindrical portions andforming a second contact, an insulating indicating member slidable in anapetrure in said cover, a first spring urging said indicating memberinto said housing and away from said cover, a fuse connected with saidcenter contact, a second spring connected with said fuse, extendingthrough a transversal opening in one of said semi-cylindrical portionsand connected with said sleeve, said second spring being bent to presenta loop having substantially parallel portions arranged adjacent saidtransversal opening, said second spring further having a curved portionsituated between said fuse and said loop and below said indicatingmember, whereby when said fuse blows said second spring forces saidindicating member out of said cover against the action of said firstspring.

JOHN BALDWIN.

WILLIAM HILLENBRAND.

